The present invention relates generally to the monitoring of defective conditions within batteries and more particularly, to the detection of such conditions from battery cell voltage output.
Apparatus for detecting most battery defects is well known. However, this apparatus usually monitors a parameter, such as abnormal voltage or current or power output relative to the overall battery, rather than to the individual cells thereof. For some types of defects, this overall battery approach is clearly inadequate. One such defect is found in a lithium type battery which often presents a dangerous pressure buildup therein when one or more of its cells has an abnormally low voltage output. The conventional approach for monitoring this defect is to mechanically sense the pressure within the overall battery and then appropriate corrective action is initiated at some critical pressure level. Because the operating tolerances of the mechanical pressure sensor are very wide, the critical pressure level of this approach must be significantly lower than desired to attain the required safety factor.